1. Field of the Invention
The present invention relates to a three-dimensional modeling apparatus and method using a grid structure, and more particularly, to a three-dimensional modeling apparatus and method by which a three-dimensional image having a similar shape to that of an actual object is formed in coordinate space formed of a grid structure.
2. Description of the Related Art
Three-dimensional modeling is generating of a three-dimensional image by using several input devices. In general, in order to digitize a shape generated through a plot as a three-dimensional image, the shape is sketched in a two-dimensional form from several points of view and then is generated as three-dimensional data based on the sketch by using various modeling tools. In this procedure, a different shape from a desired shape may be set. Thus, various studies for easily performing three-dimensional modeling without using sketches and complicated three-dimensional modeling tools have been made.
First, a technology for automating a two-dimensional sketch as a three-dimensional model has been developed. In the technology, an image of a finished two-dimensional sketch model that is shown in a drawing is divided into lines and dots, and faces are recognized using geometric information so that the three-dimensional model can be generated. When the technology is used, the image of the two-dimensional sketch model having a simple shape is easily converted into the three-dimensional model. However, it is not easy to represent a hidden portion of a model or a model having a hole in a two-dimensional sketch. There is also a technology for generating a three-dimensional model by differentiating edges and vertexes of the three-dimensional model by using trajectory information about a two-dimensional input device and additional information about a variation of speed and angle of the two-dimensional input device when a sketch is made using dots and lines on a two-dimensional plane. However, in these three-dimensional model re-constitution methods, it is not easy to generate a free curved surface. ‘Teddy’ that is a sketching system for generating a free curved surface analyzes and enlarges a circumferential line of a two-dimensional sketch so as to generate information about a thickness of the two-dimensional sketch, thereby generating a three-dimensional model. However, in a technology for generating three-dimensional data by using a two-dimensional sketch, information not entered is automatically generated, and thus, a three-dimensional model having a different shape from a desired shape may be generated.
In order to overcome the above-described problem, a sketch that is a base for modeling is made in a three-dimensional form. In the method, in order to generate a desired three-dimensional model, a curved surface model is generated and the curved surface is modified by an additional input so that a desired three-dimensional model can be generated. When the three-dimensional input device is used, due to consistency between the input device and the generated model, an intuitive sketch may be made. However, input data of the three-dimensional input device always contains an error of location in a depth direction of the three-dimensional model, due to incorrect recognition of a depth cue. Thus, a method of reducing an input error while using an advantage of the three-dimensional input device is needed.